1. Field of the Invention
The present invention relates to a particle measurement apparatus, and more particularly to an apparatus for measuring the aggregation capability or aggregation rate of platelets and other blood corpuscles.
2. Description of the Prior Art
Because of the precise picture it provides of the aggregation reaction, knowledge of the size and numbers of clumps (aggregates) of platelets and other such agglutinable blood corpuscles is essential for diagnosing various diseases. For this purpose, there are known blood platelet aggregability measurement apparatuses that measure such aggregates of particles. In a conventional apparatus for measuring platelet aggregability, for example, a sample cuvette containing a platelet solution is irradiated by a visible ray, and light transmitted and scattered from a wide area that includes many aggregates is converted to electrical signals by a light receiving element, and the intensity thereof is used to determine platelet aggregation.
Measuring as it does the intensity of light transmitted and scattered from a wide area that includes large numbers of aggregates, a drawback of the prior art is that although the size and the number of aggregates are faithful indicators of quantitative changes in the aggregation reaction, both quantities cannot be measured on a time-series basis. Moreover, because in the early stages of the aggregation reaction the intensity of scattered light from large numbers of non-aggregated blood platelets is much stronger than the intensity of scattered light from the small number of aggregates, are prevented changes in aggregation, from accurately being ascertained. In practice, with conventional measurement apparatus, such changes cannot be established even when there are aggregates of 30 to 40 percent of the platelets.